This section provides background information related to the present disclosure which is not necessarily prior art.
FIG. 1 is a view showing an example of a conventional lighting apparatus. The lighting apparatus 9 is directly connected to an AC power source 1 without using a separate drive circuit, and LEDs 2, 3 and 4 and LEDs 5, 6 and 7 are connected in parallel with their polarities reversed. Voltage is adjusted as needed via a resistor 8. The LEDs 5, 6 and 7 emit light when a positive (+) voltage is applied thereto, and the LEDs 2, 3 and 4 emit light when a negative (−) voltage is applied thereto.
Such a lighting apparatus is advantageous in that an LED lighting apparatus can be easily implemented without using a separate drive circuit for converting AC into DC, but poses a problem in the use of a dimmer (see FIG. 2). For instance, if light is dimmed to 5V when 10V is required to drive the LEDs 5, 6 and 7, no current conduction occurs. If a dimmer adapted to set the conduction time by on/off is used, the LEDs 5, 6 and 7 basically emit no light at 10V or less, so that their emission time is limited. In addition, the conduction time limitation imposed by the dimmer may cause problems such as flickering.